Operational amplifiers (opamps) are a useful and versatile building block in analog signal processing circuits. With progressively lower supply voltages, the opamp output signal swing may undergo severe limitations.
One possible approach to increase the output swing is to adopt a fully differential opamp topology, which also improves the supply noise/disturbance rejection. A fully differential structure may, however, involve an extra circuit, namely a common-mode feedback (CMFB) circuit to set the common-mode voltage at different high-impedance nodes that are not stabilized by the negative differential feedback.